We study the technology and property of NLO materials based on DAST (4-dimethylamino-N-methyl-stilbazolium tosylate): namely, a monocrystal, nanocrystals, and polymeric nanocomposites. These materials are very promising because their high nonlinear coefficients higher than that of traditional LiNbO3. We have considered the methods of preparation and the modifications of DAST nanocrystals under the synthesis conditions in solutions. The modifications of DAST crystals are determined by the hype of solvents, precipitation conditions, and the used surfactant. The obtained nanocrystals are mixed with polymers, and homogeneous transparent films are fabricated.